Cook the pasta in a large pan of boiling water according to pack instructions, adding the peas for the last 3 mins. Meanwhile, flake the trout and set aside, then mix the yogurt with the horseradish, salt and pepper.
Drain the pasta, then return to the pan and stir in the trout and yogurt, letting the heat of the pasta warm the sauce. Tastes great with a crisp green salad.
Trout is packed with omega-3s, making this a heart-healthy meal.